This application details approaches to the characterization of metalloenzymes from a number of species, e.g., bovine, equine and Bacillus (carboxypeptidase, alcohol dehydrogenase, thermolysin) and others, both to discern their mechanisms of action and to uncover general laws concerning the coordination of metals in enzymes as it pertains to their functions. This program in general biochemistry will encompass studies of the possible functional role of horse metallothionein, a Cd and/or Zn containing protein first isolated in this laboratory 20 years ago. These studies will be carried out side by side with those on analogous enzymes and proteins isolated by us from man, e.g., human carboxypeptidase, alcohol dehydrogenase, metallothionein and zinc proteins from human serum, on the metabolism of human leukemic cells and their constituent zinc proteins. These investigations of human biochemistry will extend those in general biochemistry and serve to investigate the roles of metalloenzymes in pathology.